Nearly 55,000 commuters must continue to find detours around the closed Liberty Bridge, after PennDOT officials announced they would delay its re-opening indefinitely. The agency said on the recommendation of engineering experts, additional safety measures will be included in the construction project.
The bridge has been closed since Sept. 2, when sparks from a steel-cutting operation ignited a tarp and plastic pipe, causing damage to a nearby structurally important beam.
PennDOT District 11 Executive Dan Cessna said construction of an external bracing system to the beam will provide “redundancy” when crews begin a lateral jacking process.
Cessna said in order to realign the beam, workers will apply about 400-500 degrees of heat. He said the process is complex and for safety sake will not be rushed.
“The heat straightening process that we are going to utilize is very complex. It will be very methodical and slow,” Cessna said. “As we determine how this damaged chord reacts to the heat, then that will determine how successful the repair is going.”
If the process is unsuccessful, crews will cut the chord.
During the lateral jacking process, the beam must support two million pounds of force. Cessna expects the bridge to move 1-2 inches, and said that, too, will be a slow process.
“It may be like an eighth inch at a time,” Cessna said.
Jacking could begin as early as this weekend. Cessna said after conduct research, PennDOT wasn’t able to find anywhere that had experienced the same kind of beam damage.
“Some of this has been a theoretical debate about what’s right for the structure because there is no textbook where we can look to determine what the fix can be,” he said.
If the heating process is successful, Cessna said crews will be able to attach steel and reopen the bridge to traffic. He anticipates the heat straightening could lead to a better permanent solution for the 88-year-old bridge.
PennDOToriginally estimatedthe Liberty Bridge project to cost around $80 million. The contractor, Joseph B. Fay Co., is being fined $213,600 daily until the bridge is reopened. The company is also paying for around 16 engineering organizations that Cessna said have been brought to help with the construction.
The construction fire is still under investigation by the Occupational Safety and Health Administration.
